Classifier system



July 17, 1962 CROFT 3,044,622

CLASSIFIER SYSTEM Filed June 17, 1959 4 Sheets-Sheet 1 INVENTOR. GeorgeM. Croft yyy Ew vzg July 17, 1.962 G. M. CROFT 3,044,622

CLASSIFIER SYSTEM Filed June 17, 1959 4 Sheets-Sheet 2 INVENTOR.

George M. Croft BY v 2.??

July 17, 1962 G. M. CROFT 3,044,622

CLASSIFIER SYSTEM Filed June 17, 1959 4 Sheets-Sheet 5 Fig.3.

m I nml INVENTOR George M. Croft BY M ATTORNEY)" July 17, 1962 G. M.CROFT CLASSIFIER SYSTEM 4 Sheets-Sheet 4 Filed June 17, 1959 INVENTORGeorge M. Croft A ATTORNEY! Patented July 17, 19 82 3,044,622 CLASSIFIERSYSTEM George M. Croft, Fox Chapel Borough, Pa, assignor to Maine, Ina,Sharpsbnrg, Pa, a corporation of Pennsylvania Fi led Suzie 17, 1959,Ser. No. 821,059 Claims. (El. 2&9-144) This invention relates to aclassifier system in which solid state particles to be sorted areaccompanied by a gas, generally air, to assist in the classifyingaction. More particularly, this invention pertains to apparatus andmethod for such a classifier system utilizing cooperating rotating andfixed means for separation and rejection of oversized particles, on theone hand, and segregation and removal of particles of predeterminedfineness, on the other hand.

In constructions made in accordance with this invention, it is possibleto classify a wide variety of materials with relative economy in termsof cost of equipment and expense of operation. In addition to suchflexibility, this invention provides means for segregating relativelywide size ranges of a given material for selection of an end product ofdesired size, or size range, with improved division between wantedmaterial, even when very fine, and unwanted oversize material. Moreover,such advantages are obtainable with quieter acting, less vibration andmore readily controllable classifying action. The classifier systern ofthis invention may be used separately by itself on ground or ungroundmaterial supplied thereto from storage or elsewhere for classification;or it may be used in a circuit with any of a variety of impactpulverizers where the operation is to include both classifying andgrinding in a continuous cycle.

Other objects, features and advantages of this invention will beapparent from the following description and the drawings, which areillustrative only, in which FIGURE 1 is a view in elevation of oneembodiment of a classifier system of this invention;

FIGURE 2 is a plan view of the embodiment shown in FIGURE 1 taken alongline IIII thereof;

FIGURE 3 is a view in section taken along line III- III of FIGURE 1;

FIGURE 4 is a view taken along line IVIV of FIG- URE 3;

FIGURE 5 is a view taken along line V--V of FIG- URE 4;

FIGURE 6 is a view in elevation of a portion, partly broken away, of arotating selector shown in the foregoing embodiment;

FIGURE 7 is a view in elevation of a modified rotating selector takenalong line VIIVII of FIGURE 8;

FIGURE 8 is a plan view of the modified rotating selector shown inFIGURE 7; and

FIGURE 9 is a schematic view of a grinding and classifying operationutilizing a classifier system embodi ment of this invention.

Referring to FIGURES 1 to 6, the embodiment illustrated thereincomprises a vertical circular vessel 10 which may have a door opening onone side thereof closed by a cylindrical door 11. Vessel 10 is supportedon a frame 12 and receives fresh or raw material through a feedsubassembly 13 optionally positioned on the right or left hand side asillustrated in FIGURE 2. subassembly 13 comprises a hopper 14communicating with the interior of a feed conduit 15 in which a feedscrew 16 is positioned for rotation in a feeding direction at a selectedspeed by a variable speed electric motor drive 17 connected to feedscrew 16 by a rotating'belt or cable 18. A support 19 maintainssubassembly 13 at a desired height which in this illustration enablesflange 20 of conduit 15 to be connected to a mating flange 21 on abranch pipe 22. leading into an extension pipe 23 communicah ingtangentially with the interior of vessel 10. A cap 2 on pipe 23 supportsan air blow pipe 25 which receives air from an air blower (see FIGURE 9)to propel feed tangentially into vessel It). Pipe 23 is connected to aninlet pipe 26 carried by vessel 10 and communicating as aforesaid withthe interior thereof through an opening 27.

As shown, vessel 10 is provided with a duplicate set of pipes 22, 23 and26 at from each other for tangential feeding either in the direction ofrotation of a shaft 28 or counter thereto, the duplicate feedsubassembly shown on the left hand side of FIGURE 2, being adapted forcoarser feed relative to a given desired end product size when shaft 28is rotating in a counterclockwise direction when viewed from the top.Normally, but one feed subassembly and inlet extension would be used ona selected side at one time and the flange of the unused inlet 26 wouldbe blanked off by a flange cover. Less coarse feed material wouldpreferably be fed into vessel 10 at a lower point such as thatillustrated by the level of pipes 29 or 30, progressively finer rawmaterial being fed in at progressively lower points but above avertically adjustable funnel 311. In some cases with relatively finefeed material, or ones of relatively light weight, such as mica, thefeed preferably is supplied directly to an impact grinder before theground material is introduced into vessel 1%. When classifier w is tosegregate relatively fine end product, the shaft 28 preferably isrotated in a clockwise direction when viewed from the top and the fineoverhead end product is discharged through a riser 32 at the top ofvessel 10. On the other hand, counterclocliw'ise rotation of shaft 28provides a less fine overhead end product for comparable feed to theclassifier. Whenever vessel 10 is not connected in the circuit of animpact grinder or pulverizer, feed material containing a range ofparticles of varying sizes may be fed directly to the classifier shownfor classification and oversized particles separated in vessel It) sinkto the bottom 48 and pass out through an opening 33 and outlet pipe 34.Bottom 48 preferably has the portion thereof away from opening 33 tiltedin the direction of that opening to facilitate movement of oversizeparticles out of vessel 10 through outlet 34. Hence, such classifierembodiment is very flexible and useful, especially where a number ofdifferent substances may have to be classified therein at respectivelydifferent times.

Shaft 23 is journaled in. thrust bearings 35 and 36 respeotively at thebottom and top of vessel It) and extends downwardly through the bottombearing, with suitable packing therein, for fixed engagement by drivenpulleys 37 driven by bolts 38 at a selected speed in a selecteddirection by an electric motor speed reducer set 39 mounted in a cabinetsupport 40 with suitable provision therein for proper tensioning of thebelts 38. The lowest end of shaft 28 may be supported in a cup bearing41 sup ported on a stand 42. Such mounting of shaft 28 ininimizes thepower required for driving the shaft and the members carried thereby andany tendency to vibrate.

A distributor disc 43 is fixed to shaft'28 and vertically adjustablethereon. The outer edge 44 of the distributor disc is variably spacedfrom the inside of funnel 31, to define an annular opening between discand funnel which normally is set larger when coarser material is to beground and smaller for finer material. The disc spins particles whichland thereon and provides an opportunity for classification by strip airentering the opening through a pipe '45 to remove finer and lighterportions in the course of the upward path of such air. Further, somestrip air may find its Way up through outlet 34 depending upon thecircuit in which vessel Iii may be connected. When grinding somewhatgummy or sticky materials the 3 upper surface of disc 43 may be providedwith upstanding radial vanes to assist in such distribution. Strip airontering through pipe preferably is conducted through a stationary ver"cal sleeve 46 in spaced relation to the lower end of shaft 28 withinvessel 10. A cap (-7 is affixed to shaft 28 in spaced relation to theupper edge of sleeve so that the strip air from pipe 45 makes arcentrant turn and is discharged downwardly toward the bottom it? ofvessel 16' before moving upwardly through funnel 31 and the annularopening between the inside of the funnel and edge 44. Such strip airhelps also to sweep any oversize particles on bottom into the opening33.

A rotating selector is fixed to shaft 23 and, as shown, comprises fourtiers, each of which has a plurality of radial arms welded to a hubfixed to the shaft. Each of the arms is in the form of an angle in crosssection and the outer tips of the arms in each tier support a circularband 52 connected to certain spaced arms in that tier by bracl: ts 53.The bands 52 expose the ends of the radial arms 5'3 and close the spacebetween each tier as shown in 6. The underside of the segmental spacesbetween the arms in th lowermost ticr are closed by a round closureplate fastened thereto as by welding. Preferably, the outer ends of theradial arms above the lowest tier are vided with a vane 55 slopingdownwardly and in a direction away from the horizontal flange of therespective arms. The arms 55% in all of the tiers have the horizontalflange-s thereof pointing in the same direction and the arms in eachtier are angularly spaced relative to the arms in the next lower tier,in general echelon hion. For coarser grinding operations requiring l."ger end product, the selector 49 may be rotated in the direction ofarrow with the vertical flanges of the arms Ell, leading. Conversely,for finer predetermined end product specification on the same feedmaterial, selector 4-9 may be rotated in the opposite direction byshaftZfi.

An annular shroud 57 extends from an annular cover etwec-n riser 32 andthe side walls of vessel 10 and the uppermost tier in selector Theshroud is provided with a c ntral opening communicating with riser 32and 9. depending cylindrical flange 59 so that any material entering,for example, through opening 27 must pass through at least one tier ofthe rotating arms 54). In the case of coarser feeds, the tendency ofoversize particles tl erein is to move readily toward the bottom ofvessel 30 during v-Jhi h time any sufiiciently light particles thereinare stripped therefrom by strip air from pipe or strip air which mayintroduced above funnel 31 as through the pipe or Stl if such pipe isnot being used a feed inlet. Generally, the wider the range between thesize of the feed particles and the size of the esnred rd product, thegreater the number of tiers of arms 3 preferred in selector 49, whilewith relatively fine for/ s, a single tier maybe suitable.

In place of selector particularly where selection is not particularlydifficult, a fan type selector 69 such as that illustrated in FIGURES 7and 8 may be utilized. In selector the upper and lower hubs 61 areprovided with radially extending arms 62 forming upper and lower spid rsto the outer ends of which arms 62 vertically extending paddle or fanblades 63 are afiixed to reject ovcrsizcd particles while permittingsulficiently small or light ones to enter the center of selector 6% andpass upwardly between the upper arms 62 to the center of th shroud andthe riser thereabove.

End product material flowing upwardly through riser 32 exits through aproduct outlet 64 from whence it passes by pipe 65 to a collector whichmay be in the nature of an air filter bag collector from which the endproduct material is taken for storage or sacking or other treatment. Apipe 66 may also be provided and connected to an air blower toadditionally control the pressure relation between the top and bottom ofvessel 10, suitable valves being provided in all of the air connectionsfor the purpose of sh ttting them otf or regulating them as desired fora selected operation. Generally, the pressure in vessel it) willdecrease as one moves toward the top thereof. Further, in addition to,or in lieu of, fresh or original feed, recycle material from apulverizer be fed to vessel 10 through a pipe Such as pipe 29 connectedto the off-take from a grinder or pulverizing mechanism.

An operative hook-up of the classifier device of FIG- URES l to 6 isschematically illustrated in FIGURE 9. Therein, a blower 6'7 driven at aselected speed by a motor 63 supplies air to a manifold 69 which in turnthrough suitable valves 70 supplies air to the respective air receivingmembers described above at respectively selected pressures which may beindicated by manometers 71. In the case of fine material to be ground,which may be relatively light so that oversize particles therein, forexample, take too long to move down through vessel 16, such material maybe fed through a feeder subassembly 13 directly into a feed chamber 72in which there is a high pressure aspirating nozzle 73 comprising aportion of a jetting gun 74 directed against an interstitial target mass75 in an impact pulverizer 76 such as that disclosed in my copending-United States patent application Serial No. 8l9,04l filed June 9, 1959,for Impact Pulverizer, now Patent No. 2,991,946. Oversize material fromvessel 10 passing out through outlet 34 may enter feed chamber 72 alongwith any feed from feeder 13' and strip air may enter feed chamber 72through a pipe 77, which may be connected to manifold 69. Grinding airat much higher pressure is supplied through pipe 78 to nozzle 73.Material from pulverizer 76 may be Withdrawn through an off-take pipe 79and returned to the interior of vessel 10 through pipe 29. In this way,a continuous combined grinding and classifying cycle is obtainable withthe economy and flexibility provided by the classifier system of thisinvention. Such classifier system may also be used separately as aclassifier on fresh feed carried into the interior thereof by feedersubassembly 13, or at some other height preferably above funnel 31 forrespective segregation and removal of sutficiently fine material at thetop and of oversize particles at the bottom. Or, fresh feed may beintroduced by pneumatic pressure into the interior of vessel 10 at suchselected height for classification in accordance with this invention.

Various details and changes may be made in the illustrated apparatus andsteps, and other embodiments pro vided, without departing from thespirit of this invention or the scope of the appended claims.

I claim:

1. In an air classifier system, apparatus comprising, in combination, acylindrical vessel having a vertical axis and an opening at the topthereof, a shaft extending into said vessel along said axis, means forrotating said shaft in a selected direction at a selected speed, aselector having a plurality of horizontal tiers of radial arms connectedto said shaft for rotation therewith, the arms in each of the respectivetiers being angularly displaced relative to the arms in another tier,said arms being angles in cross section facing in the same direction andhaving a vane at the outer ends thereof in the upper tiers inclineddownwardly and peripherally, a plate closing the bottom of said selectorand rotatable therewith, an annular shroud extending from the top ofsaid selector to said vessel around said opening, a covering for thespace between said tiers respectively, a funnel in said vesselpositioned below said selector, a disc distributor connected to saidshaft for rotation therewith having an outer edge in selectively spacedrelation to the inside of said funnel, means for supplying strip air tosaid vessel at least below said funnel, means for feeding material to beclassified tangentially into said vessel, an outlet for oversizematerial below said funnel, and an outlet for sufiiciently fine material in airborne suspension above and communicating with the interiorof said selector through said opening,

whereby material may be classified and oversize particles thereinrejected.

2. In a gas suspension classifier system, apparatus comprising, incombination, a cylindrical vessel having a vertical axis and a finematerial outlet opening, a shaft ex tending into said vessel along saidaxis, means below the bottom of said vessel for rotating said shaft in aselected direction at a selected speed, a selector having a plurality ofhorizontal tiers of radial arms connected to said shaft for rotationtherewith, a plate closing the bottom of said tiers and rotatabletherewith, a fixed annular shroud covering the top of said tiers andextending to a sealing position around said opening to put it intocommunication with the interior of said selector, a funnel in saidvessel positioned below said selector, a disc distributor connected tosaid shaft for rotation therewith having an outer edge in spacedrelation to the inside of said funnel, means for supplying air to saidvessel at least below said funnel, means for tangentially supplyingmaterial to be classi-fied into said vessel, an outlet for oversizematerial below said funnel, and an outlet for fine material in gasbornesuspension communicating with said opening.

3. In a gas suspension classifier system, apparatus cornprising, incombination, a vessel having a vertical axis, a shaft extending intosaid vessel along said axis, means for rotating said shaft at a selectedspeed, a selector having at least one horizontal tier of radial membersconnected to said shaft for rotation therewith, a plate closing thebottom of said selector and rotatable therewith, an annular memberpositioned in said vessel, an annular shroud extending from the top ofsaid selector to the upper end of said vessel, a discoidal distributorconnected to said shaft for rotation therewith having an outer edge inspaced relation to the inside of said annular member, means forsupplying air to said vessel below said selector, said annularmember'and distributor together defining a selected annular gaptherebetween below said selector and above the lower end of said vessel,means for feeding material to be classified into said vessel above saidannular member and distributor, an outlet for oversize material, and anoutlet in said vessel adjacent said selector for fine material ingasborne suspension communicating with the interior of said selectorthrough said shroud.

4. In a rising gas suspension classifier system, apparatus comprising,in combination, a vessel having a verti- I cal axis, a shaft extendinginto said vessel along said axis,

pered ring funnel in said vessel positioned below said s'elector, adiscoidal member connected to said shaft having its outer edgepositioned adjacent said funnel, means for supplying a risingcurrent ofair to said vessel below said funnel, means for feeding materialperipherally into said vessel above said funnel, an outlet for oversizematerial in the lower portion of said vessel, and outlet means in theupper portion of said vessel for selected fine material in airbornesuspension in the upper portion of said vessel, said last-named outletcommunicating with the interior of said selector.

5. In an air classifier system, apparatus comprising, in combination, acylindrical vessel having a vertical axis and an opening at the topthereof, a shaft extending into said vessel along said axis, means forrotating said shaft, a selector having at least one horizontal tier ofoutwardly extending arms connected to said shaft for rotation therewith,a member closing the bottom of said selector and rotatable therewith, aseal extending from the top of said selector to said vessel aroundsaidopening, a' funnel in said vessel positioned below said selector, adiscoiclal distributor connected to said shaft for rotation therewithhaving an outer edge in selectively spaced relation to the inside ofsaid funnel, means for supplying air to said vessel at least below saidfunnel, means for tangentially supplying material to be classified tosaid vessel, an outlet for oversize material below said funnel, and anoutlet for sufliciently fine material in airborne suspension above andcommunicating with the interior of said selector through said opening.

References Cited in the file of this patent UNITED STATES PATENTS1,149,463 Pardee Aug. 10, 1915 2,069,398 Wallace Feb. 2, 1937 2,487,088Andrews Nov. 8, 1949 2,739,708 Denovan Mar. 27, 1956 FOREIGN PATENTS 316,901 Germany Dec. 13, 1919 951,121 France Apr. 11, 1949

